Process of producing metal bodies



C. L. GEBAUER. PROCESS OF PRODUCING METAL BODIES.

APPLICAUON FILED MAY 17, 1917- Patantedlune8,l920.

T MW re 0 am Mr m 5% Ni 0/ M Z TF7 r: sM Hm N M60, 0 f L CHARLES L. G-EBAUEB, 0F CLEVELAND, OHIO.

Specification of Letters Patent.

rnocnss or rnonucme METAL Bonms.

Patented June 8, 1920.

Application filed May 17, 1917. Serial No. 169,176.

To all whom it may concern:

Be it known that 1, CHARLES L. GEBAUER, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Processes of Producing Metal Bodies, of which the following is afull, clear, and exact description, reference being had to the accompanying drawings.

This invention relates to a new process of producing metal bodies, the metal bodies in question being themselves of peculiar construction and valuable properties. In my copending application filed April 12, 1916, Serial No. 90,585, I have described and claimed an alloy and process of producing same wherein a metal of high fusing point and a metal of lower point being first reduced to finely pulverized form are mixed intimately together, pressed into form and finally heated to such a temperature as to melt the more fusible ingredient and cause it to embrace the less fusible ingredient. Further experiments have disclosed the fact that it is not necessary in all cases to mix two metals together, but that if the less fusible ingreclient be reduced to pulverized form and very forcibly compacted, the more fusible ingredient can be introduced or sweated into 1 the mass from the outside, at least sufliciently for practical purposes in many applications. This procedure is especially convenient practically from the fact that most of the high fusing point metals can be obtained rather easily in pulverized form whereas it is frequently very difiicult to secure the more fusible metals in this condition.

While I do not limit myself to the use of any particular metal or of any combination or combinations of metals, I prefer to use and for practical purposes have used a combination of tungsten and platinum more frequently than any others, as for example in the construction of parts for electrical instrumentssuch as spark points or arcing terminals. In the performance of my said invention, assuming the above named materials to be employed, the tungsten is utilized in the finely divided crystalline form just as it is derived from the reduction of tungstic oxid by hydrogen. This finely granular material is first compacted under great pressure, as by a hydraulic or other press, into the exact shapes and sizes required. The articles are then placed in a suitable heating device such as an electric furnace, in close surface contact with sheets or plates or layers of the other substance. Thus in the case of spark points, a disk of platinum foil of the approprlate size is laid on top of each member, while for rods or bars the foil is wrapped around the same, or for irregular shapes a layer of finely divided platinum (or other metallic substance) can be sprinkled thereon. The furnace then being heated to the regular temperature, the more fusible metal is first melted and then absorbed by the less fusible article. A reducing or neutral atmosphere is maintained in the furnace during this operation so as to prevent any such oxidation of the metal as would impede close surface contact. The rate and amount of absorption can be regulated by the porosity of the articles, this being dependent upon the coarseness of the pulverization and the pressure employed in compacting. In the case of tungsten, molybdenum, and the like metals, which are reduced b hydrogen, the crystal size can be modified y proper regulation of temperature during the reduction as is well known. A sufiiciently close compacting must be given in all cases to enable the articles to withstand reasonable handling prior to the sweating or impregnating operation.

In addition to the convenience gained by the ability to use each metal in the form in which it is most cheaply obtained commercially, there is the consideration that less of the more fusible substance is employed than when the two substances are mixed uniformly together, and this substance is located in large proportion at theplace where it is most useful, namely adjacent to the surface of the resulting article.

A great many combinations of metals can be employed, though preferably they should be so chosen as not to be mutuall soluble under the conditions described. can see that m invention will be most useful in cases w ere tun sten, molybdenum, and the like constitute t e more refractory element, and platinum, silver or gold the more fusible element, but I do not confine myself thereto. Ordinarily the more fusible metal constitutes from 3 to 10 percent. of the weight of the less fusible metal but these proportions are also susceptible to variation according to the particular use in view.

In the accompanying drawings, Figure 1 is an elevational view of a contact point embodying my invention, and Fig. 2 is a view venience in illustration of a portion of the working surface thereof on an exaggerated scale.

In Fig. 2 I have attempted to illustrate the structural nature of the working surface of a contact formed in accordance with my invention. The main body portion of the contact point consists of highly refractory material A, illustrated as very 'finely divided, as tungsten in the crystalline form, and the working surface is formed of a layer of more fusible material B, as of platinum, applied thereto and fused into the interstices between the tungsten particles in the above described manner, the tungsten particles havin been previously closely compacted together under great pressure. This results in a composite contact point having a main body portion A of finely divided closely compacted particles and a worln'ng surface B of another material in the nondivided state, the latter material flowing into and completely filling the interstices between the finely divided particles near the surface of the main body rtion. For conhave shown the more fusible metal B as only penetrating the main body to a comparatively short depth below the surface although in practice the impregnation probably goes much deeper. In fact, by pro rly proportioning the size and porosity o the absorbing particles or by continuing the sweating operation long enough the main body may become impregnated throughout. In all cases the impregnation is more complete near the surface than deeper down, and the composition of the contact varies in a graded manner from the surface inwardly, the variation taking place progressively from the layer B to the extent of the impre ation.

Having thus descri ed my invention, what I claim is 1. The process of producing metallic bodies which consists of molding a finely disintegrated metallic constituent of high melting point to the desired form, applying a layer of a constituent of lower melting point to the surface of the body and subjecting the composite body thus formed to a temperature suflicient to melt the constituent of the lower melting point.

2. The process of producing metallic bodies which consists of molding and compacting a finelydis'integrated metallic constituent of high melting point to the desired form under pressure, applying a layer of a constituent of lower melting point to the surface of the body, and subjecting the composite body thus formed to a temperature sufficient to melt the less refractory constituent under non-oxidizing atmospheric conditions.

3. The process of producing composite metallic bodies which consists of molding and compacting a finely divided metallic element of a bi h melting point into the desired form unger great pressure, applying a layer of a less refractory element to the body, and sweating the less refractory element into the more refractory element by subjecting, under non-oxidizing conditions, the composite body to a temperature intermediate the melting points of the constituentelements.

4. The process of producing composite tungsten bodies, which consists of molding and compacting finely divided tungsten into the desired form under great pressure, applying a layer of an elementv of lower melting point than that of tungsten to the surface of the body thus formed, and sweating the less refractory element into the tun sten body by subjecting the composite b0 y in a neutral atmosphere to a temperature sufliciently high to melt the less refractory element but lower than the melting point of tungsten.

5. The process of producing composite tungsten and platinum bodies which consists in molding and compacting finely divided tungsten to the desired form under great pressure, applying a coating of platinum to the body thus formed, and sweating the platinum into the tungsten b subjecting the composite body in a neutral atmosphere to a temperature intermediate the melting points of tungsten and platinum.

In testimony whereof, I hereunto aflix my signature in the presence of two witnesses.

CHARLES L. GEBAUER. Witnesses:

LUom'TC. EHRKE, H. B. McGILL. 

